The soot in the atmosphere exhibits irregular fractal agglomerate structure. In this study, the reconstruction of agglomerate structure is observed for soot generated by spark discharge in both propene ozonolysis and photooxidation systems. This process makes the agglomerate soot more compact, and is possibly caused by the peroxy radicals and hydroxyl radicals generated from propene oxidation. The result furthers our understanding of the atmospheric aging process of soot agglomerate. Since the reconstruction directly changes the size distribution of soot, it may induce important changes to the soot's physical and chemical properties in the atmosphere.